Roberts has been historically so far conservative, so now he gets one decision which is disagreed and he gets skewered. There are lots of decisions I disagree with as I tend to be more liberal.
I would love to get five minutes in this guy's mind to see why he decided as he did. There are many theories likecommere but the tax theory is sound. The government taxes many things income , alcohol, gasoline etc. The power to tax clearly lies with the fed give if they choose to use it.
You can tax to encourage or discourage behavior so the decision though disagreeable to many does have a basis. The Congress can in whole or part repeal the law.